// @flow
// '@flow'为flow注解插件的前置配置，表示：启用flow插件
// 添加成员的类型注解
// yarn flow ：解析js =》/dist/js
function sum(a: any, b: number) {
    return a + b
}

console.log(sum(100, 200));
// console.log(sum('100', '200'));

// Cannot call `sum` with `'100'` bound to `a` because string [1] is incompatible with number [2]. [incompatible-call]